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Post by captbob on Feb 9, 2008 23:23:38 GMT -5
This is a rock tumbling forum right?  I did a search and couldn't find any information about tumbling obsidian. So if any of you have done it, here come some questions. Should it be tumbled/treated like glass? Are there any extra steps or precautions that I may want to take on my first try at it? I've read it may be gassy and need burping more so that most other rocks. Anyone have a tried and true recipe for rotary tumbling of obsidian? I have a few different types, there wouldn't be a problem mixing them in the same tumble would there? I'd like to tumble some rather larger pieces... thoughts on this? Should I use ceramic media on this tumble or just pellets? Would rainbow obsidian be worth throwing in the mix? I figure it would tumble the same, but would any of the colors show after being tumbled? Sawing... any words of wisdom on cutting obsidian? I'd like to make some slabs out of this stuff as long as I've got it out. Seems to be a fairly soft rock on the Mohs scale, can I speed my saw up for this material? Thank you for any opinions and knowledge you may have on this! |
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Post by johnjsgems on Feb 9, 2008 23:38:07 GMT -5
Obsidian is volcanic rock. Treat it like glass and you should be all right. Most people polish with cerium. The one year we did shows in Oregon everyone had a different polish recipe. It seems like obsidian from different locations tumble better with different polishes. If cerium doesn't work try the whole arsenal. I met an old guy that tumbles Apache tears and polishes with cerium and Karo syrup. Use plenty of media to cushion and check often as it tumbles fast.
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earthdog
Cave Dweller 
Don't eat yellow snow
Member since June 2006
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Post by earthdog on Feb 9, 2008 23:50:39 GMT -5
I have done alot of Obsidian. Always had good luck with it as long as you tumble it alone and use a butt load of pellets. I have used cerium and A.O. polish. The A.O. took about a week longer to get a shine than the cerium did.
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Post by captbob on Feb 9, 2008 23:59:43 GMT -5
One more question as long as we're talking about tumbling...
I've been cutting tiger eye for my next load. Any problem adding some tiger iron to the mix?
I know the hematite in the tiger iron is a bit softer, but not by that much. Okay to put them together or should I wait and do a separate load for the tiger iron?
Thanks for all replies!
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RockyBlue
fully equipped rock polisher
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Post by RockyBlue on Feb 10, 2008 1:07:21 GMT -5
Hey capn.
Check with Cher! She does an excellent job on Apache Tears,and has an excellent reciepe for tumbling...............Rocky
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earthdog
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Don't eat yellow snow
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Post by earthdog on Feb 12, 2008 13:38:33 GMT -5
Guess you didn't read what I wrote. You can add anything you want to the load of obsidian but when they turn out with white looking edges from banging against other rocks which may be harder don't say that you weren't told...
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Post by captbob on Feb 12, 2008 13:45:30 GMT -5
I wrote:
One more question as long as we're talking about tumbling...
I've been cutting tiger eye for my next load. Any problem adding some tiger iron to the mix?
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I was asking about adding tiger iron to a tiger eye tumble. Not even this noobie would think of putting that stuff in with obsidian!
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huffstuff
fully equipped rock polisher
Member since August 2007
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Post by huffstuff on Feb 12, 2008 14:07:09 GMT -5
Ooops, captbob, I misunderstood your second question, too. I'm not sure I know the difference between tiger eye and tiger iron. I gotta go do some research!
Amy
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earthdog
Cave Dweller
Don't eat yellow snow
Member since June 2006
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Post by earthdog on Feb 13, 2008 10:19:35 GMT -5
You can throw tiger eye with tiger iron.
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rollingstone
starting to spend too much on rocks
Member since July 2009
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Post by rollingstone on Feb 13, 2008 17:53:46 GMT -5
Hi Captbob, Obsidian tumbles up nicely, but is a bit finicky. Yes, you can mix all different types of obsidian together (and glass too, for that matter). Sure, give the rainbow a try too, I can't see why it wouldn't work fine. I would highly recommend not using big pieces, they really enhance the chipping of this chip-prone material. When I tumbled obsidian I found that a starting weight of 35 grams (about 1.5 ounces) was the maximum for a successful tumble. I did run some pieces a bit bigger, up to 50 grams (about 2 ounces), but I ended up breaking them in half because I felt they were causing too much chipping in the coarse grind. Can't answer your sawing questions as I prepared my rough with a hammer and chisel. Here's a link to a thread on some obsidian I tumbled. It gives a recipe there, and further down the thread I reply to some questions people had. Good luck! -Don forum.rocktumblinghobby.com/index.cgi?board=Pictures&action=display&thread=12375&page=1 |
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Post by captbob on Feb 13, 2008 19:32:59 GMT -5
Thank you for the replies!
Earthdog, I appreciate your help. My other 15# Thumlers is scheduled to be here tomorrow, so the tiger eye AND tiger iron will go in that and get rolling.
Don, Thank you for the link to that thread. Very nice tumble there! I think that I'll work on making a batch of snowflake and mahogany obsidian. I'm sure the rainbow would tumble just fine (if I can nail the tumble!), but not sure the colors would show. It's very high grade material and I don't want to waste it.
I'll post when I start that batch. Anyone ever tumble rainbow obsidian?
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earthdog
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Don't eat yellow snow
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Post by earthdog on Feb 13, 2008 21:57:39 GMT -5
Just make sure you post a picture of all those huge tumbles set up together.
If you have any problem with the new tumblers, send it to me and I'll work out the bugs for you.
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Post by johnjsgems on Feb 13, 2008 23:19:07 GMT -5
And while we're correcting, I meant to say obsidian is volcanic glass. I think if the rainbow is nice big pieces I'd save some if not all for future cabbing or carving or something where you can cut at proper angles to best show the rainbow affect.
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